Peptide LSARLAF activates alpha(IIb)beta3 on resting platelets and causes resting platelet aggregate formation without platelet shape change
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Updated: Oct 29, 2026

Analyzing Platelet Subpopulations by Multi-color Flow Cytometry
Published on: June 10, 2025
J M Derrick1, R G Loudon, T K Gartner
1Microbiology and Molecular Cell Sciences, University of Memphis, TN 38152-6041, USA.
Abstract:
Adhesion of resting platelets to fibrinogen was enhanced by a peptide which was designed to bind near the presumptive fibrinogen gamma-chain binding site of the alpha subunit of the integrin alpha(IIb)beta3. This peptide, but not a scrambled control peptide, induced adhesion of resting platelets to fibronectin, vitronectin, von Willebrand factor, and monovalent (lacks one functional gamma-chain) fibrinogen. Resting platelets not treated with the agonist peptide did not adhere to these ligands. Agonist peptide induced adhesion of resting platelets to Fg was not secretion dependent and was inhibited by the monoclonal antibody 7E3. The agonist peptide caused aggregation of resting platelets on resting platelets adherent to immobilized Fg without causing platelet shape change. Therefore, the agonist peptide may activate alpha(IIb)beta3 by directly inducing a conformation change in the receptor on resting platelets.
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